Disinfectant

ABSTRACT

The invention relates to a water-free alcohol disinfectant capable of destroying spores. Preferably, the disinfectant also contains an additional chemical sterilization agent, e.g., hydrogen peroxide, in very low concentrations within the range of between 0.5 and 3.0 percent of the weight of the alcohol solution. The disinfectant is usable in industrial contexts for bacteriological cleaning of surfaces, for example, inner walls in pipelines, conduits, reaction vessels, and other process equipment, without corroding or chemically attacking the material in such surfaces.

This application is a 371 of PCT/IB96/00263 filed on Mar. 29, 1996.

TECHNICAL FIELD

The present invention relates to a disinfectant containing a solution ofalcohol. The invention also relates to a method of producing thedisinfectant, and use of an alcohol solution containing hydrogenperoxide in a quantity of between 0.3 and 3.0 per cent for destroyingspores and similar micro-organisms.

BACKGROUND ART

Alcohol disinfectants are known from, for example, EP-A-O 016 319 whichdescribes such an agent for cleaning wounds and similar practicalapplications. The prior art disinfectant contains a solution of alcoholto which has been added, for purposes of stabilisation, hydrogenperoxide in an amount of between 0.05 and 1 per cent of the weight ofthe alcohol solution. According to EP-A-O 016 319, it is possible, bymeans of this addition of hydrogen peroxide, to prevent the uncontrolledgrowth of spores and the like unintentionally introduced into thedisinfectant. A disinfectant similar to that described above is alsoknown from EP-A-O 252 278 which proposes, also for purposes ofstabilisation, the addition of hydrogen peroxide so as to prevent theuncontrolled growth of spores and similar micro-organisms and therebystabilise the alcohol disinfectant.

In addition to wound treatment and skin cleaning purposes, disinfectantsare also employed in industrial contexts for destroying undesired(pathogenic) bacteria and other harmful micro-organisms. In, forexample, the food and pharmaceuticals industries, extremely high demandson hygiene are often placed on the produced product, partly in orderthat the product can be consumed at all, and partly to enable it to bepacked and stored without the risk of being destroyed during its storagelife as a result of decomposition reactions occasioned bymicro-organisms and/or the uninhibited/uncontrolled growth of harmfulmicro-organisms which may unintentionally accompany the product into itspackage.

In order to satisfy the demands on product hygiene, it is therefore notleast important that the equipment which is used for producing andpackaging the product be carefully monitored and controlled and, ifnecessary or as a preventive measure, be regularly cleaned anddisinfected so as to eliminate the presence of harmful micro-organismsin the immediate vicinity of the product. It is of particular importancethat such surfaces (for example pipelines, conduits and the like) whichthe product flows in direct contact with, or otherwise comes into directcontact with during the producing and packing processes are kepthygienically clean and free of micro-organisms which risk harming theproduct. This naturally also applies to the package and the materialfrom which the package is produced.

For disinfecting and cleaning equipment employed in industrial processesof the type described above, it is known in the art to use solutions ofalcohol, such as ethanol and/or propanol. These known agents are activeagainst such micro-organisms as vegetative bacteria, fungi and viruseswhich may therefore readily be eliminated, but are incapable ofcombating spores.

Another known disinfectant and cleaning agent for industrialapplications is based on chemicals such as peracetic acid, hydrogenperoxide, formaldehyde and glutaraldehyde which are all highly activeagainst not only micro-organisms such as vegetative bacteria, fungi andviruses, but also against spores which may thus readily be eliminated bytreatment with these known agents. One problem however is that the thesesporicidal agents are highly corrosive and, as a result, also attack anddestroy the material, for example stainless steel, plastic, rubber etc.,employed in conventional process equipment.

There is thus a need in the art for a disinfectant for industrial usewhich may efficiently be employed for eliminating micro-organisms,including spores, but which at the same time does not attack and destroythe material, for example non-stainless steel, plastic, rubber etc., inthose surfaces from which the micro-organisms are to be eliminated.

OBJECT OF THE INVENTION

One object of the present invention is therefore to realise adisinfectant of the type described by way of introduction which makesfor an efficient destruction of undesired micro-organisms, includingspores, without chemically attacking the material in those surfaces fromwhich the micro-organisms are to be eliminated.

SOLUTION

This object is attained according to the present invention in that adisinfectant of the type described by way of introduction has been giventhe characterising feature that the alcohol solution employed ispractically water-free.

The term “practically water-free” used in this description and in theappended Claims is here taken to signify an alcohol solution which,while not being completely free of water, contains such a slightquantity of water as it possibly can in order that the object accordingto the invention be attained. It will be obvious to the skilled readerof this specification that absolutely water-free alcohol solutionsseldom exist in practice, since such alcohol solutions are—primarily fortechnical and economical reasons—difficult or economically indefensibleto produce, given the applications for which such alcohol solutions areoften intended. Consequently, the expression “practically water-free” inthis context implies an alcohol solution which has so little water as iswarranted for both production-engineering and economical reasons withoutjeopardising the object according to the present invention. In orderfurther to clarify and concretise the implications of this expression,it should be added that alcohol solutions of different alcohols contain,or may contain, different quantities of water without departing from thespirit and scope of the inventive concept as herein disclosed. Forexample, an alcohol solution of ethanol may contain water in quantitiesof up to approx. 4 per cent, i.e. be a 96 per cent ethanol solution,while an alcohol solution containing propanol (n-propanol and/orisopropanol) may contain water in quantities corresponding to approx. 30per cent of the weight of the alcohol solution, i.e. be a 70 per centpropanol solution.

The disinfectant according to the invention which is, like the prior artdisinfectants according to the above disclosed publications EP-A-O 016319 and EP-A-O 252 278, based on an alcohol solution thus differs fromthese prior art disinfectants in that the alcohol solution employed isto contain a reduced quantity of water or be practically water-free inthe meaning and scope as apparent from the foregoing discussion.

According to the invention, it has surprisingly proved that adisinfectant which is based on an alcohol solution which is practicallywater-free makes for efficient destruction of micro-organisms, not onlyof the type such as vegetative bacteria, fungi and viruses, but also ofspores, which have previously proved to be difficult or impossible toeliminate using prior art alcohol-based disinfectants.

The disinfectant according to the present invention has further provedto be an efficient cleaning agent in industrial applications foreliminating such micro-organisms, including spores, from the inner wallsin pipelines, conduits, reaction vessels and similar process equipment,without chemically attacking or causing corrosion in the material whichis used in such apparatuses.

According to one preferred embodiment of the present invention, thedisinfectant also includes an additional chemical destruction agent ofthe above-described sporicidal, but corrosive type, such as peraceticacid, hydrogen peroxide, formaldehyde and glutaraldehyde. In suchinstance, it has surprisingly proved that the corrosive effect of suchagents may be considerably reduced and even entirely eradicated whileretaining sporicidal activity, even at very low concentrations of thisagent. Such a “synergistic” effect is attained according to the presentinvention even at such low concentrations as between approx. 0.5 and 3.0per cent which is the preferred concentration range for this agent whenemployed in the disinfectant according to the preferred embodiment ofthe invention.

Such a particularly preferred additional chemical destruction agentaccording to the invention is hydrogen peroxide in concentrations ofbetween 0.5 and 3.0 per cent of the weight of a water-free alcoholsolution.

Further advantageous and expedient embodiments of the disinfectantaccording to the present invention have moreover been given thecharacterising features as set forth in the appended subclaims.

The present invention will now be described in greater detailhereinbelow, with the aid of a non-restrictive practical embodiment inwhich the elimination efficiency of the disinfectant according to thepresent invention is illuminated.

To a water-free solution containing either propanol (n-propanol and/orisopropanol) or ethanol, hydrogen peroxide (H₂O₂) was added inquantities corresponding to between 0.5 and 3.0 per cent of the weightof the solution. A surface (metal, plastic) was inoculated with ahydrogen peroxide resistant spore suspension of Bacillus subtilis A (BSA22), whereafter the inoculated surface was sprayed with a) water ascontrol reference and b) one of the above-produced disinfectantsaccording to the invention. After 15 min., the spore reduction effectsof the different solutions (disinfectants) was determined by washing ofthe surfaces with swabs, preparation of test dilutions, and plating onPC agar.

The results showed that hydrogen peroxide in water had a very lowreduction effect on the spores (within the range of 1 log) as comparedwith the control reference (the water), but that this effect increasedwithin the concentration range of between 0.3 and 5.0 per cent. On theother hand, hydrogen peroxide in combination with the water-freesolution of propanol (iso-propanol and/or n-propanol) or ethanoldisplayed a very good (synergistic) reduction effect between log 5 andlog 6 with BSA spores in the concentration range of between 0.5 and 1.0per cent.

It is thus apparent from the results of the described Example that thedisinfectant according to the invention is a valuable chemicaldisinfectant possessing surprisingly good destruction effects alsovis-a-vis spores. The disinfectant according to the present invention isparticularly well-suited as bacteriological and sporicidal cleaningagent also in industrial contexts for cleaning surfaces of plastic,metal and rubber without corroding or otherwise attacking and destroyingsuch surfaces. The disinfectant according to the invention is moreovereasy to produce by a simple mixing process.

It should finally be observed that the above description is not intendedto limit the present invention, various modifications and variationsbeing possible without departing from the spirit and scope of theinventive concept as this is defined by the appended Claims. Suchmodifications and variations are, however, evident and obvious to aperson skilled in the art and are thus intended to be encompassed by thescope of the appended Claims.

What is claimed is:
 1. A method for disinfecting and cleaning equipmentemployed in industrial processes without chemically attacking or causingcorrosion in said equipment, which comprises the step of contacting asurface of said equipment with a disinfectant comprising a practicallywater-free alcohol solution, hydrogen peroxide, wherein said hydrogenperoxide is present in a quantity of between 0.5 and 3.0% of the weightof said solution, and optionally a chemical destruction agent selectedfrom the group consisting of peracetic acid, formaldehyde, andglutaraldehyde.
 2. The method according to claim 1, wherein said surfaceis non-stainless steel, plastic, or rubber.
 3. The method according toclaim 1, wherein said hydrogen peroxide is present in a quantity ofabout 1% of the weight of said practically water-free alcohol solution.4. The method according to claim 1, wherein said practically water-freealcohol solution is ethanol, n-propanol, or isoponanol, or mixturesthereof.